The invention relates to a tool for preparing a multi-conductor electrical power cable for termination to and installation in a self-contained wiring device. More particularly, the invention relates to a cable slicing and spreading tool for both slicing through the outer protective sheath of a multi-conductor electrical cable and spreading apart the conductors therein for termination to and insertion into insulation displacement terminals in a self-contained wiring device.
Multi-conductor electrical cable, having a relatively thick outer protective insulating sheath covering a bare ground and a pair of insulated conductors, is currently utilized in residential and commercial structures to distribute electrical power throughout buildings and other structures. Customarily, access to and control of the electrical current in the electrical cable is effected by connecting receptacles and switches to the cable. For certain applications, the receptacles and switches utilized in making contact with the conductors of the cable are made in the form of self-contained wiring devices, sometimes called SCD devices.
For these SCD devices, the outer protective cable sheath must be sliced to expose the ground and individual insulated conductors which are then spread apart for termination to the device. Once the conductors of the cable have been spread, the self-contained receptacles and switches can be rapidly terminated to the cable. The installation time required for termination is reduced as compared to that required for installation of conventional wiring devices because there is no need to cut or strip the insulation from the individual conductors for termination to the device since the individual conductors are terminated to the devices via insulation displacement terminals which cut through the insulation on the individual conductors to make electrical contact with the conductors.
A major factor in the installation time required for wiring the SCD devices is the time spent in preparing the cable for connection to receptacles and switches. The preparation involves slicing the outer protective insulating sheath and spreading the conductors without damaging either the electrical insulation around the conductors or the conductors themselves. Where cable preparation has been done manually, it usually involved the use of a knife to slice through the exterior sheath and spread the wires apart, with the continuing danger of injury ot the electrician.
Tools have been developed to facilitate the process of slicing the sheath and spreading the conductors but generally they have not been as facile in operation as might be desired. One such tool, disclosed in U.S. Pat. No. 3,846,894, has multiple parts pivotably connected at several points. Although the tool can function for its intended purpose, it is cumbersome to handle and awkward to operate because the various parts tend to "flop" about. Further, since the tool provides for closing the device back cover over the sliced and spread cable to force the conductors into the insulation displacement terminals, it does not permit the electrician to inspect the condition of the terminations except by reopening the device or use of a "dummy" back cover.
Another wire slicing and spreading tool is described in U.S. Pat. No. 4,025,998. Although this tool functions adequately in certain respects, it is adapted to spread the cable conductors, after the slicing operation, in two planes thereby making it difficult to connect to self-contained wiring devices. It also does not permit inspection of the termination except by reopening the device or using a "dummy" back cover.
U.S. Pat. No. 4,387,746, assigned to the present assignee and the disclosure of which is hereby incorporated by reference, describes a tool representing an improvement over previous configurations in that it does not tent to "flop" about but is still somewhat bulky and may be considered by some to be cumbersome to operate. This tool also fails to provide for ready inspection of the terminations.
Accordingly, it is an object of the present invention to provide a new and improved cable slicing and separating tool for preparing an electrical conducting cable for termination to a self-contained electrical wiring device. It is also an object of the invention to provide ;such a tool which requires relatively few independent parts to fabricate and, when assembled, has only two basic moving parts.
It is another object of the invention to provide a new and improved cable slicing and spreading tool of the foregoing type, which permits both the cable slicing and spreading function and the cable-to-device termination function to be performed by a single tool, yet enable the electrician or installer to readily inspect the terminations before the device is closed. It is a further object of the invention to provide such a tool which requires only a single pivot point and requires exertion of an generally uniform force for completing the slicing and spreading function.
It is yet another object of the present invention to provide a new and improved cable slicing and spreading tool which is comprised of a relatively few structural parts, the principal ones of which may be conveniently made by metal casting techniques.
The foregoing and other objects and advantages of the invention are set forth herein but may also be realized from the present disclosure or from practice with the invention.